Surgical gown tie attachment

ABSTRACT

There is disclosed the use of bonding and the placement of a reinforcement piece to meet AAMI levels 3 and 4 barrier properties in surgical gowns and similar articles formed from thermally sensitive laminate barrier materials that are composed of thermoplastic polymers. The reinforcement piece is placed on the side opposite of the tie and the bonding uses a point-unbonded pattern.

BACKGROUND OF THE INVENTION

Surgeons and other healthcare providers often wear an over garmentduring operating procedures in order to enhance the sterile condition inthe operating room and to protect the wearer. The over garment istypically a gown that has a main body portion to which sleeves and a tiecord are attached. The tie cord encircles the wearer at the waist tokeep the gown in place. In order to prevent the spread of infection toand from the patient, the surgical gown prevents bodily fluids and otherliquids present during surgical procedures from flowing through thegown.

Surgical gowns were originally made of cotton or linen, were reusableand were sterilized prior to each use in the operating room. Adisadvantage of the materials used in these types of gowns is that theytend to form lint, which is capable of becoming airborne or clinging tothe clothes of the wearer, thereby providing another potential source ofcontamination. Additionally, costly laundering and sterilizationprocedures were required before reuse.

Disposable surgical gowns have largely replaced the reusable linensurgical gown and many are now made in part or entirely from fluidrepellent or impervious fabrics to prevent liquid penetration or “strikethrough”. Various materials and designs have been used in themanufacture of surgical gowns to prevent contamination in differentoperating room conditions. Surgical gowns are now available in a varietyof different levels of imperviousness and comfort.

Gowns made from completely impervious material provide a high degree ofprotection, though a surgical gown constructed of this type of materialis typically heavy, expensive, and uncomfortably hot to the wearer. Insome surgical gowns, certain portions such as the shoulders and backpanels may be of a lighter weight material in order to provide forbetter breathability and help reduce the overall weight of the gown.Generally, however, the higher the breathability of the material, thelower the repellency of the material.

Different types of surgical procedures expose the healthcare provider todifferent levels of blood and/or fluid exposure, so it is not feasibleor economical to use the same type of surgical gown for every surgicalprocedure conducted by the healthcare provider. New guidelines haverecently been created for the rating of the imperviousness of surgicalgowns, gloves and the like, to provide guidance to healthcare providers.The Association for the Advancement of Medical Instrumentation (AAMI)has proposed a uniform classification system for gowns and drapes basedon their liquid barrier performance. These procedures were adopted bythe American National Standards Institute (ANSI) and were recentlypublished as ANSIA/AAMI PB70: 2003 entitled Liquid Barrier Performanceand Classification of Protective Apparel and Drapes Intended for Use inHealth Care Facilities, which was formally recognized by the U.S. Foodand Drug Administration in October, 2004. This standard established fourlevels of barrier protection for surgical gowns and drapes. Therequirements for the design and construction of surgical gowns are basedon the anticipated location and degree of liquid contact, given theexpected conditions of use of the gowns. The highest level ofimperviousness is AAMI level 4, used in “critical zones” where exposureto blood or other bodily fluids is most likely and voluminous. The AAMIstandards define “critical zones” as the front of the gown (chest),including the tie cord attachment area, and the sleeves and sleeve seamarea up to about 2 inches (5 cm) above the elbow.

The main body portion and the sleeves of a surgical gown are usuallyproduced separately and joined together in some manner at seams in theshoulder area. The sleeves are commonly made from a flat piece of fabricthat is folded upon itself and joined together at a seam that runs thelength of the sleeve from the shoulder to the wrist, prior to attachmentto the main body portion. A single tie cord or a pair of tie cords isalso usually attached to the main body portion of the gown. A single tiecord is used to encircle the wearer at the waist and tie to itself inorder to keep the gown in position during use. Two tie cords are alsoused to encircle the wearer at the waist and tie to each other. Theseams and the tie cord attachment point are areas where many gowns havebeen known to fail the AAMI test procedure.

A number of surgical gowns are currently marketed which are assembledthrough the use of ultrasonic seam sealing. Ultrasonic seam sealingbonds the layers of material together sufficiently for strength but thebonds do not pass ASTM-1671-b; the bacteriophage penetration resistancetest, a test that is now required to meet the new AAMI level 4protection standards, nor do they pass the hydrohead test, AATCC testmethod 127-1998, for AAMI level 3 protection. This is particularly truefor the sleeve seams and tie cord attachment point.

It is clear that there exists a need for a gown having tie cordattachments bonded in a manner that is more impervious than currentmethods and that meets AAMI levels 3 and 4.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary gown 100 to be worn during a medicalprocedure as seen from the front.

FIG. 2 illustrates an exemplary gown 100 to be worn during a medicalprocedure as seen from the back.

SUMMARY OF THE INVENTION

In response to the foregoing difficulties encountered by those of skillin the art, we have successfully used a point-unbonding bond patternwith and without a reinforcement patch on medical gowns at the tieattachment point such that they will pass AAMI level 3 (AATCC 127-1998hydrohead) 4 testing (ASTM 1670 and 1671-b).

DETAILED DESCRIPTION OF THE INVENTION

The present invention involves the use of bonding and the placement of areinforcement piece to meet AAMI levels 3 and 4 barrier properties insurgical gowns and similar articles formed from thermally sensitivelaminate barrier materials that are composed of thermoplastic polymers.

Many surgical gowns are made from thermally sensitive laminate barriermaterials composed of thermoplastic polymers. While such barriermaterials may be in the form of thermoplastic polymer spunbond fabrics,thermoplastic polymer meltblown fabrics, and various combinations ofsuch spunbond and meltblown fabrics, a particularly desirable form ofthese barrier materials incorporate one or more thin, breathable filmsthat provide desirable levels of resistance to penetration by liquidsand pathogens while also providing satisfactory levels of breathabilityand/or moisture vapor transmission.

These thin and breathable films are commonly made from thermoplasticpolyolefins like polyethylene and polypropylene and copolymers thereofbecause of their relatively low cost and ability to be processed.Polyethylene is generally used in the film production and the film iscommonly “filled” with calcium carbonate, various kinds of clay, silica,alumina, barium carbonate, soldium carbonate, magnesium carbonate, talc,barium sulfate, magnesium sulfate, aluminum sulfate, titanium dioxide,zeolites, cellulose-type powders, kaolin, mica, carbon, calcium oxide,magnesium oxide, aluminum hydroxide, pulp powder, wood powder, cellulosederivatives, chitin and chitin derivatives, to increase breathability.Fillers produce microscopic pores in the film upon stretching toincrease porosity. Unfortunately, these thin and breathable films areconsidered to be thermally sensitive because they have a tendency tobecome compromised by heat and/or or pressure. When these films areincorporated into laminate barrier materials by sandwiching themtogether with various combinations of other materials such as, forexample, spunbond fabrics, meltblown fabrics and combinations thereof,the resulting laminate barrier materials are generally considered to bethermally sensitive as well. This characterization is particularlyimportant for post-laminate formation processing steps. That is,manufacturing operations that convert the thermally sensitive barrierfabrics after such films are formed into the laminate barrier fabrics.For example, when thermally sensitive barrier materials are convertedinto gowns or other articles utilizing thermal point bonding and/orultrasonic bonding techniques or when components such as, for example,tie cords or other features are attached to the articles, the breathablefilms of barrier laminate are frequently compromised such that they solonger provide desired levels of barrier to liquid penetration andpathogens.

“Spunbond” refers to fabric made from small diameter fibers which areformed by extruding molten thermoplastic material as filaments from aplurality of fine, usually circular capillaries of a spinneret with thediameter of the extruded filaments then being rapidly reduced as by, forexample, in U.S. Pat. No. 4,340,563 to Appel et al., and U.S. Pat. No.3,692,618 to Dorschner et al., U.S. Pat. No. 3,802,817 to Matsuki etal., U.S. Pat. Nos. 3,338,992 and 3,341,394 to Kinney, U.S. Pat. No.3,502,763 to Hartman, and U.S. Pat. No. 3,542,615 to Dobo et al.Spunbond fibers are generally not tacky when they are deposited onto acollecting surface. Spunbond fibers are generally continuous and haveaverage diameters (from a sample of at least 10) larger than 7 microns,more particularly, between about 10 and 20 microns.

“Meltblown” fabric is formed by extruding a molten thermoplasticmaterial through a plurality of fine, usually circular, die capillariesas molten threads or filaments into converging high velocity, usuallyhot, gas (e.g. air) streams which attenuate the filaments of moltenthermoplastic material to reduce their diameter, which may be tomicrofiber diameter. The meltblown fibers are then carried by the highvelocity gas stream and are deposited on a collecting surface to form aweb of randomly dispersed meltblown fibers. Such a process is disclosed,for example, in U.S. Pat. No. 3,849,241 to Butin et al. Meltblown fibersare microfibers which may be continuous or discontinuous, are generallysmaller than 10 microns in average diameter, and are generally tackywhen deposited onto a collecting surface.

Laminates of spunbond and meltblown fabrics, e.g.,spunbond/meltblown/spunbond (SMS) laminates and others are disclosed inU.S. Pat. No. 4,041,203 to Brock et al., U.S. Pat. No. 5,169,706 toCollier, et al, U.S. Pat. No. 5,145,727 to Potts et al., U.S. Pat. No.5,178,931 to Perkins et al. and U.S. Pat. No. 5,188,885 to Timmons etal. Such a laminate may be made by sequentially depositing onto a movingforming belt first a spunbond fabric layer, then a meltblown fabriclayer and last another spunbond layer and then bonding the laminate in amanner described below. Alternatively, the fabric layers may be madeindividually, collected in rolls, and combined in a separate bondingstep. Such fabrics usually have a basis weight of from about 0.1 to 12osy (6 to 400 gsm), or more particularly from about 0.75 to about 3 osy.Multilayer laminates may also have various numbers of meltblown(abbreviated as “M”) layers or multiple spunbond (abbreviated as “S”)layers in many different configurations and may include other materialslike films (abbreviated as “F”) or coform materials (see U.S. Pat. No.4,100,324 for descriptions of exemplary “coform” materials), e.g. SMMS,SM, SFS, etc.

An exemplary method of forming a film includes a co-extrusion filmapparatus that forms the film with multiple layers consisting of skinand core layers. Typically the apparatus will include two or morepolymer extruders. In one method of fabrication, the film is extrudedinto a pair of nip or chill rollers. In another method the film isextruded onto a chilled roll which can have a smooth or matte finish.Typically, the film as initially formed will have an overall thicknessof approximately 25 to 60 micrometers with, in the case of multilayerfilms, the total skin or bonding layer having an initial thickness thatmay be about 3% to 30% of the total thickness. Other film makingprocesses known to those skilled in the art may be used as well,including cast embossing, chill and flat casting and blown filmprocesses.

From the coextrusion film apparatus the film is directed to a filmstretching unit such as a machine direction orienter (MDO), which is acommercially available device from vendors such as the Marshall andWilliams Company of Providence, R.I. Such an apparatus has a pluralityof paired stretch rolls that move at predetermined speeds that mayrotate faster, slower or at the same speed relative to each other.Typically the stretch rolls move at a progressively faster speeds toprogressively stretch and thin the film in the machine direction of thefilm, which is the direction of travel of the film through the process.The stretch rolls are generally heated for processing advantages.

The temperatures to which the film is heated while stretching willdepend on the composition of the film as well as the breathability andother desired end properties of the laminate. In most cases the filmwill be heated to a temperature no higher than 5 degrees ° C. below themelting point of the core or “B” layer in the film. The purpose forheating the film is to allow it to be stretched quickly without causingfilm defects. The amount of stretching will depend on the polymericcomposition, but, in general, the film may be stretched to about 300% ormore of its original length (that is, a one cm length, for example, willbe stretched to 3 cm) but less than the amount that tends to result infilm defects. For most applications, for example, the stretch will be toat least 200% of the original film length and, frequently, in the rangeof about 250% to 500%.

The multilayer stretch-thinned film may be attached to one or moresupport layers to form a multilayer film/nonwoven laminate as describedabove. For example, a conventional fibrous nonwoven web formingapparatus, such as a pair of spunbond machines, may be used to form thesupport layer. The long, essentially continuous fibers are depositedonto a forming wire as an unbonded web and the unbonded web is then sentthrough a pair of bonding rolls to bond the fibers together and increasethe tear strength of the resultant web support layer. One or both of therolls are often heated to aid in bonding. Typically, one of the rolls isalso patterned so as to impart a discrete bond pattern with a prescribedbond surface area to the web. The other roll is usually a smooth anvilroll but this roll also may be patterned if so desired.

Once the multilayer film has been sufficiently thinned and oriented andthe support layer has been formed, the two layers are brought togetherand laminated to one another using a pair laminating rolls or othermeans. As with the bonding rolls, the laminating rolls may be heated.Also, at least one of the rolls may be patterned to create a discretebond pattern with a prescribed bond surface area for the resultantlaminate. Generally, the maximum bond point surface area for a givenarea of surface on one side of the laminate will not exceed about 50percent of the total surface area.

The process described above may be used to create a three layerlaminate. The only modification to the previously described process isto feed a supply of a second fibrous nonwoven web support layer into thelaminating roll on a side of the multilayer film opposite that of theother fibrous nonwoven web support layer. Alternatively, as with theother layers, the support layer may be formed directly in-line. Ineither event, the second support layer is fed into the laminating rollsand is laminated to the multilayer film in the same fashion as the othersupport layer.

Exemplary processes and materials for forming thin films and laminatesmay be found in commonly assigned U.S. Pat. Nos. 5,188,885, 5,213,881,5,271,883, 5,464,688, 5,695,868, 6,037,281, 6,309,736, 6,653,523 and6,764,566, incorporated herein in their entirety.

FIG. 1 illustrates a typical gown 100 to be worn during a medicalprocedure as seen from the front. The gown 100 includes a collar 110,the cuffs 120, the primary tie cord 130 and a primary tie cordattachment area 140. The shoulder seams 150 linking the sleeves 160 tothe main body 170 are also visible. FIG. 2 illustrates a typical gown100 to be worn during a medical procedure as seen from the back. In FIG.2 the shoulder seams 150 linking the sleeves 160 the main body 170 arevisible as are the sleeve seams 180 running from the shoulder seams 150to the cuffs 120 which are used to produce the sleeves 160. FIG. 2 alsoshows a secondary tie cord 180 and secondary tie attachment area 190(not in the AAMI critical zone).

Previous tie cord sealing methods tended to damage the layers of thegown and to impair the liquid resistance of the bond to a point that thegown failed the AAMI level 3 or 4 test at the bond, or to beprohibitively expensive. These methods included ultrasonic or thermalpoint bonding and adhesive bonding. The inventors believe, though do notwish to bound by that belief, that the former methods tend to bondmaterials through their entire thickness, thus disrupting the structureto a relatively high degree. Since many surgical gowns include a filmlayer in order to increase the penetration resistance of the gown andbecause film layers tend to be relatively weak, the robust bonding usedpreviously tended to damage this layer and increase liquid penetration.In the case of adhesive bonding the manufacturing challenges and expenseare relatively great since adhesives tend to be expensive and timeconsuming to apply and can have detrimental effects on manufacturingfacility cleanliness.

As noted above, the process conditions will vary depending on thematerials of construction. For example, the current thermoplasticpolymeric materials commonly used in disposable gowns and for componentssuch as, for example, tie cords that are presently attached to suchdisposable gowns, are typically nonwoven fabrics formed frompolypropylene and/or polyethylene and have a basis weight typicallyranging from about 0.5 (17 gsm) to about 1.5 osy (51 gsm).

Desirably, the tie cord material may be a folded 1.0 osy (34 gsm) SMSmaterial made as described above. Fabric for the fabrication of gownsmay be, for example, made of random copolymer spunbond, a three layer(Catalloy®/polyethylene/Catalloy®) or “ABA” calcium carbonate filledfilm, and a spunbond/meltblown/spunbond (SMS) layer. This “SFSMS” maybonded together to form the gown with the SMS against the skin. Thespunbond layer and film may have a basis weight of between 0.2 and 1.0osy (7 and 34 gsm) or more particularly about 0.6 osy (20.3 gsm). TheSMS layer may have a basis weight of between 0.5 and 1.5 osy (17 and 51gsm) or more particularly about 0.75 osy (25.4 gsm).

The inventors have found that the attachment of a reinforcement piece onthe side opposite the tie cord attachment side can provide sufficientassistance to the barrier properties such that the attachment pointpasses the hydrohead test. The reinforcement piece may be formed fromvarious materials including films, papers, meltblown fabrics, etc.provided, however that the material from which the piece is made has ahydrohead above the AAMI level 3 standard. The piece may also have anadhesive for ease of application. The reinforcement piece may be, forexample, a wax-treated paper available under the tradename “Fastape”from the Avery-Dennison Specialty Tape Division, 250 Chester St.,Painesville, Ohio 44077. Fastape® paper also has an adhesive.

The reinforcement piece must be sufficiently large to cover the area ofattachment of the tie cord. Generally a piece from about 1.5 inches to2.5 inches (38 to 64 mm) in width to about 2.5 to 4 inches (64 to 102mm) in length should suffice, giving an area of at most 10 square inches(645 square centimeters).

In addition to the reinforcement piece described above for AAMI level 3testing, the inventors have found that a change in the bonding patternis required in order to successfully reach AAMI level 4 requirements.Previous thermal bonding patterns have used “male” patterns. Theinventors have found that “female” or point-unbonded (PUB) patternsprovide greatly improved bonding for the purposes of the AAMI level 4.The method of attaching the reinforcement piece is desirably by bondingit ultrasonically with the new PUB bonding pattern.

Traditional “male” thermal point bonding generally involves passing afabric to be bonded between a heated calender roll and an anvil roll.The calender roll is usually, though not always, patterned in some wayso that the entire fabric is not bonded across its entire surface, andthe anvil roll is usually flat. As a result, various patterns forcalender rolls have been developed for functional as well as aestheticreasons. One example of a pattern has points and is the Hansen Penningsor “H&P” pattern with about a 30% bond area with about 200 bonds/squareinch as taught in U.S. Pat. No. 3,855,046 to Hansen and Pennings. TheH&P pattern has square point or pin bonding areas wherein each pin has aside dimension of 0.038 inches (0.965 mm), a spacing of 0.070 inches(1.778 mm) between pins, and a depth of bonding of 0.023 inches (0.584mm). The resulting pattern has a bonded area of about 29.5%. Anothertypical point bonding pattern is the expanded Hansen Pennings or “EHP”bond pattern which produces a 15% bond area with a square pin having aside dimension of 0.037 inches (0.94 mm), a pin spacing of 0.097 inches(2.464 mm) and a depth of 0.039 inches (0.991 mm). Another typical pointbonding pattern designated “714” has square pin bonding areas whereineach pin has a side dimension of 0.023 inches, a spacing of 0.062 inches(1.575 mm) between pins, and a depth of bonding of 0.033 inches (0.838mm).

“Point unbonded” or “PUB” bonding means a fabric pattern havingcontinuous bonded areas defining a plurality of discrete unbonded areas.The fibers or filaments within the discrete unbonded areas aredimensionally stabilized by the continuous bonded areas that encircle orsurround each unbonded area and the unbonded areas are specificallydesigned to afford spaces between fibers or filaments within theunbonded areas. A suitable process for forming the pattern-unbondednonwoven material of this invention includes providing a nonwoven fabricor web, providing opposedly positioned first and second calender rollsand defining a nip therebetween, with at least one of said rolls beingheated and having a bonding pattern on its outermost surface comprisinga continuous pattern of land areas defining a plurality of discreteopenings, apertures or holes, and passing the nonwoven fabric or webwithin the nip formed by said rolls. Each of the openings in said rollor rolls defined by the continuous land areas forms a discrete unbondedarea in at least one surface of the nonwoven fabric or web in which thefibers or filaments of the web are substantially or completely unbonded.Stated alternatively, the continuous pattern of land areas in said rollor rolls forms a continuous pattern of bonded areas that define aplurality of discrete unbonded areas on at least one surface of saidnonwoven fabric or web. Examples of point unbonded patterns areillustrated in U.S. Pat. No. 5,858,515 to Stokes et al.

The amount of bonding for use herein is between about 20 and 30 percent,preferably about 25 percent. An exemplary PUB pattern for use inreaching the AAMI level 4 criteria is characterized by multiple unbondedareas of 0.030″ (0.762 mm) open space and a 0.010″ (0.254 mm) seal lineper every 0.040″ (1.016 mm), producing a bond area of 25%.

The bonding “window” or conditions under which bonding takes place, isbetween the point at which holes will form in the fabric or where itwill fail the AAMI levels 3 and 4 testing, and the point at which tieswill be easily pulled off of the gown after bonding. The examples belowwere bonded using a Branson 900 series ultrasonic welding machine byBranson Ultrasonics Corporation, of Danbury Conn. The Branson 900 iscontrolled by setting the pressure and weld or contact time between thebonding points and the material. The pressure and contact time for useherein are between 50 and 90 psi and between 0.05 and 0.25 seconds,respectively, more particularly between 60 and 75 psi and 0.1 and 0.2seconds, still more particularly about 65 psi and about 0.18 seconds.

The examples below show that the addition of a reinforcing piece allowsgowns to pass the AAMI level 3 test and that adding PUB bonding allowsthe gown to pass AAMI level 4 testing.

Test Methods

AATCC test Method 127-1998: This test uses a Hydrostatic PressureTester, apparatus available from Alfred Suter Co., PO Box 350, RamseyN.J. 07445-0350. An alternative but similar tester, the TextestHydrostatic head Tester, is available from Schmid Corp., 140-B VentureBlvd, Spartanburg, S.C. 29301.

The Suter apparatus is an inverted conical well equipped with a coaxialring clamp to fasten the cloth specimen under the well bottom. Theapparatus introduces water from above the specimen over an area 114 mmin diameter at a rate of 10.0±0.5 mm of hydrostatic head per second. Amirror is affixed below the specimen to enable the operator to ascertainpenetration of the specimen by drops of water. A valve is provided forventing the air in the well.

A minimum of three fabric specimens should be taken diagonally acrossthe width of the fabric to be tested. Cut specimens at least 200 by 200mm to allow proper clamping. The specimen should be conditioned at 21°C. and 65 percent relative humidity for at least 4 hours before testing.The specimen is clamped in the apparatus with the surface to be testedfacing the water, which is at 21° C. The apparatus is turned on andwater is introduced at the stated rate. Droplets appearing within 3 mmof the edge of the specimen should be disregarded and the pressure atwhich droplets penetrate the fabric in three different places isrecorded. The pressure is reported as the height (in millimeters) ofwater above the fabric. An average should be calculated for each sample.The AAMI level 3 standard of 50 cm must be reached in order to pass thetest.

ASTM tests 1670 and 1671-b, procedure A: These tests are identicalexcept that 1670 uses synthetic blood and 1671 uses Phi-X174bacteriophage.

The test uses a penetration test cell available from Wilson Road MachineShop, Rising Sun, Md. The cell has a capacity of about 60 ml. In thetest cell, the specimen acts as a partition separating the challengefluid from the viewing side of the penetration cell. An annular flangecover with an open area to allow visual observations of the specimen,and a transparent cover are included. The cell body has top port forfilling and a drain valve for draining the penetration test cell. Thepenetration cell is further specified in Test Method F903.

The fabric specimen is placed in the penetration cell with the layerthat is normally outermost facing the back (solid flange) part of thecell where the challenge fluid is placed. The cell is filled through thetop port with the challenge fluid and observed for 5 minutes. Air isthen supplied to the top port and the sample held at 13.8 kPa (2 psig)for 1 minute and the pressure released. If liquid penetration is not yetseen, the sample is allowed to stand for 54 minutes and observed. Ifbacteriophage is the test fluid, the sample is subsequently assayedusing a 0.5 ml sample size onto agar for 6 to 18 hours at 35 to 37° C.to test for passage of fluid that is not observable to the unaided eye.

Example Materials Kimberly-Clark Ultra® Surgical Gowns

The Kimberly-Clark Ultra® Impervious gown is made from 1.5 osy (51 gsm)polypropylene SMS and has a reinforcing section in the sleeves and chest(the AAMI “critical area”). The reinforcing material is a 1 milpolyethylene film. The sleeve is bonded film to film and turned insideout so the SMS is nearest the skin.

Kimberly-Clark MicroCool® Surgical Gowns:

Kimberly-Clark MicroCool® surgical gowns are made of random copolymerspunbond, a three layer (Catalloy®/polyethylene/Catalloy®) calciumcarbonate filled film, and a polypropylene spunbond/meltblown/spunbond(SMS) layer. This “SFSMS” is bonded together to form the gown with theSMS against the skin. The random copolymer of which the outermost layerof spunbond material is made is a 2.5 weight percent ethylene-propylenecopolymer known as R532-35R, from the Dow Chemical Company of Midland,Mich. No treatments are applied to the fabric. The spunbond layer andfilm each had a basis weight of 0.6 osy (20.3 gsm). The SMS layer had abasis weight of 0.75 osy (25.4 gsm).

Tie Cord:

The tie cord to be bonded to the gown was a folded 1.0 osy (34 gsm) SMSmaterial. The material was folded either once for a double layer offabric, or twice for a triple layer of fabric. The outer layer(spunbond) was made from a 2.5 weight percent ethylene-propylenecopolymer known as R532-35R, from the Dow Chemical Company and the outerlayer is treated with an antistat and a fluorochemical to reduce surfacetension. Prior to bonding to the gown, a additional piece of tie cordmaterial was bonded to the tie cord near an end to produce a “Y” shapedend for bonding to the gown on both upper end of the Y. The Y wasflattened out onto the gown for bonding at two points on the branches ofthe Y but near the stem of the Y.

EXAMPLE 1 Basic Ultra

A double folded SMS tie cord was bonded to an Ultra® surgical gown at aweld time of 0.175 seconds and a pressure of 65 psi using a point bondpattern. The bonded area was tested according to AATCC 127-1998. Twelveout of 12 samples failed.

EXAMPLE 2 Ultra with Fastape and PUB Bonding

A double folded SMS tie cord was bonded to an Ultral® surgical gown at aweld time of 0.175 seconds and a pressure of 65 psi using a PUB bondpattern with 25 percent bond area as described above. A 2.5 inch by 4inch piece of Fastape® adhesive tape was placed below the tie cord bondsite prior to bonding. The bonded area was tested according to AATCC127-1998. Twelve out of 12 samples passed.

As will be appreciated by those skilled in the art, changes andvariations to the invention are considered to be within the ability ofthose skilled in the art. Examples of such changes are contained in thepatents identified above, each of which is incorporated herein byreference in its entirety to the extent it is consistent with thisspecification. Such changes and variations are intended by the inventorsto be within the scope of the invention. It is also to be understoodthat the scope of the present invention is not to be interpreted aslimited to the specific embodiments disclosed herein, but only inaccordance with the appended claims when read in light of the foregoingdisclosure.

1. A surgical gown having an AAMI critical zone comprising a tie cordbonded to said gown at a bond in said critical zone wherein said bondpasses AATCC test Method 127-1998.
 2. The surgical gown of claim 1further comprising a reinforcement piece on a side opposite said tiecord.
 3. The surgical gown of claim 3 wherein said reinforcement piecehas an area of at most 10 square inches.
 4. The surgical gown of claim 1wherein said bond is produced with a PUB pattern.
 5. The surgical gownof claim 4 wherein said bond has an area of between about and 30percent.
 6. The surgical gown of claim 5 wherein said bond has an areaof about 25 percent.
 7. A surgical gown having a tie cord, areinforcement piece on the side opposite said tie cord, and a tie cordbond area where said tie cord is bonded to said gown and saidreinforcement piece, wherein said tie cord bond area passes ASTM test1671-b.
 8. The surgical gown of claim 7 wherein said gown comprises apolyolefin microfiber layer.
 9. The gown of claim 8 wherein saidmicrofiber layer is a spunbond layer which is made from polyethylene,polypropylene or an ethylene-propylene copolymer.
 10. The gown of claim7 wherein said gown further comprises a filled film.
 11. The gown ofclaim 10 wherein said tie cord has an outer layer that is treated withan antistat and a fluorochemical to reduce surface tension.
 12. The gownof claim 7 wherein said bond is made at a pressure between 50 and 90 psiand for a weld time between 0.05 and 0.25 seconds.
 13. The gown of claim12 wherein said bond is made at a pressure between 60 and 75 psi and fora weld time between 0.1 and 0.2 seconds
 14. The gown of claim 12 whereinsaid bond is made at a pressure of about 65 psi for a weld time of about0.18 seconds.
 15. A surgical gown having an AAMI critical zone ofsleeves and chest and comprising a tie cord bonded to said gown with abond at a tie cord bonding area in said critical zone, wherein said bondis produced with a PUB pattern having an area of about 25 percent and ata pressure of about 65 psi and a weld time of about 0.18 seconds, saidgown is made from polypropylene SMS and has a reinforcing section ofpolyethylene film in said AAMI critical zone.
 16. The gown of claim 15wherein said tie cord bonding area passes ASTM test 1671-b.
 17. A methodof bonding a tie cord to a surgical gown comprising the steps of placingsaid tie cord on said gown and thermally bonding them together at a tiecord bonding area with a PUB pattern, wherein said tie cord bonding areapasses AATCC test Method 127-1998.
 18. A method of bonding a tie cord toa surgical gown comprising the steps of placing said tie cord on saidgown, placing a reinforcement piece on a side opposite said tie cord,and thermally bonding them together at a tie cord bonding area wheresaid tie cord is bonded to said gown and said reinforcement piece with aPUB pattern, wherein said tie cord bonding area passes ASTM test 1671-b.